The lily of the valley has thug tendencies and can probably outrun your landscaping fabric. Each of the other plants you mention will sooner or eventually outgrow its slit. If you dream of generous clumps of Hosta offset by those lovely ferny fronds of Dicentra - go for a reasonably thick cover of fine to medium nugget-size bark mulch over a generous helping of aged commercially made compost (to ensure no weed seeds).

Well, form should follow function, so some study of where people walk and stand when they visit you should tell you where your surfaces need to be. You can make the whole thing look dramatically different by using curves, flares, circles, and the like. For an idea of how good a walkway can look, check out the concurrent thread linked below(though I think in your case pavers would look fine). An attractive landing at the base of the steps would anchor the whole thing. In fact, considering what a job it would be to take out those existing stairs, maybe it's all you should do, and you can stain the steps. And far from leaving the planting question to the last, you should consider whether and if so how you can incorporate plants into your new design. Something like a planter box, or space in the dirt for a clematis or small shrub (depending whether you like a manicured or cottage look - imagine a clematis framing the garage door), might be nice on either side of the driveway, assuming you wish to pull the walkway away from the house a little. Or leave that pad there and put in a pair of nice containers with annuals. Search this forum (or the whole internet for that matter) for pathway/walkway ideas, check out the local paver manufacturer websites for ideas, and get out a pen and paper and make a plan view. Obviously cost is an issue, and what you can accomplish will depend on what you can DIY or afford. KarinL Here is a link that might be useful: walkway pictures

This is an opinion, not a scientific fact because I can't test all these products myself. I don't think the stabilizers are worth their cost or effort. Many of these types of things (stabilizers and sealers) exist in order to generate profit in the industry. Notice how in later years there is a push in many industries to general subscriptions instead of one-time fees. In the landscape industry, it's sealers and stabilizers that need to be reapplied every so often. Fear is the predominant motivator as people think, "what bad thing will happen if I don't have this extra protection??" Look at all the landscape materials of antiquity. Things lasted better than ever without all the extra "products."

I don't know the answer to your question, sorry. I have a similar path and also have similar problems walking the lawnmower across/along the path. One thing I have which makes things slightly easier for walking is that instead of 18"x18" concrete tiles, I use larger (wider) pieces of flagstone (about 30"x18"), and I find that I can easily walk along the path because the flagstone is wide enough and appropriately placed so that I end up stepping on it, and not the pea-stone. Yes, the pea-stone is difficult to walk on, but most of the time my feet end up landing on the flagstone. However, the lawnmower is still a bit of an issue for me. I would suggest that if you can't find a solution to increase stability , you could try replacing the stepping tiles that you have with something larger similar to what I have, or put a second line of stepping tiles alongside the existing tiles. This would at least help with the walking because the stable part of the path is wider. It may also help with the lawnmower a bit because both wheels will run along the tiles for part of the time. Not a great solution, I know, but if you are stuck. Also you may find that the pea-stone over time works its way into the garden and the garden dirt, mulch works its way into the pea-stone, and then weeds start to grow in the pea-stone - you might want to consider putting something else along the edge of the path to better contain each side.